Polish prime minister Donald Tusk appears to have clinched a second term in office for his centrist, pro-European Civic Platform party, a historic first in the country's post-communist era. One exit poll gave Tusk's party nearly 40% support, well ahead of its main challenger, the conservative Law and Justice party of Jaroslaw Kaczynski.

The poll showed Kaczynski's party winning 30% of the votes. Tusk's apparent victory comes after he has presided over four years of impressive economic growth. The country managed to keep growing even in 2009, when the rest of the European Union fell into recession.

The country has also seen a boom in construction in its major cities, thanks to preparations to co-host the Euro 2012 football championship next year. Poles have watched as dilapidated train stations have received facelifts and modern stadiums have mushroomed in some cities.

"It is the highest honour for me and for Civic Platform that we will be working for the next four years for all of you, regardless of who you voted for today," Tusk told jubilant supporters. "In the next four years we will work twice as hard."

Foreign minister Radek Sikorski, a leading member of Tusk's party, called the party's showing "confirmation that our concept of European cooperation and modernisation of Poland is finding approval."

The government has privatised some state industries and has tried to build better ties with EU allies as well as Russia. However, its critics fault it for lacking the will to make deeper reaching reforms.

A new leftwing party, Palikot's Movement, was in third place in the exit poll with just over 10%. Led by entrepreneur and maverick lawmaker Janusz Palikot, the party has been the surprise of the election season, gaining popularity in a short time on promises to fight the power of the Roman Catholic church in society and other socially liberal causes.

Despite Palikot's strong showing, Sikorski said Civic Platform is interested in continuing its coalition with the Polish People's Party, its junior partner of the past four years. The Polish People's Party is a small farm-based group with conservative social values that favours the interests of farmers. It has 8.2% support in the exit poll.

Kaczynski, the twin brother of president Lech Kaczynski, who died in a plane crash last year, acknowledged his defeat at his party's election night gathering.

"We respect the result of the election, but our task for the next four years will be to convince millions of Poles that changes are needed," Kaczynski said.

"I am deeply convinced that the day will come when we will succeed," he added. "Sooner or later we'll win because we are simply in the right."

The only other party that would make it into parliament is the Democratic Left Alliance, with 7.7% in the poll. That marks a sharp decline from elections four years ago, when it won 13%.

Tusk's apparent re-election makes his party the first ever to win two consecutive terms since the fall of communism in 1989.

In the first 18 years after communism, Poland had 13 different governments, a new one every 17 months on average. Now it seems that Tusk could govern for eight years in a row.